There are few downsides to turbochargers, but there are some. One of them is how they perform in cold environs. That is the issue that owners of GM’s four-cylinder turbocharged engines are experiencing. Especially in regions that reach lows below 0 degrees.
What is happening is that the charge air cooler, better known as an intercooler, can ice over. When that happens, it restricts airflow. The results are a loss of power, throttle lag or hesitation, and other issues, according to GM Authority.
An intercooler cools the compressed charge from the turbo. The cooler the charge, the denser it becomes, giving more power. Remember, an engine is kind of like a big vacuum cleaner. More air in and then out gives more power. With the intercooler iced over, there is less charged air coming in and then out of the combustion chambers.
The affected three- and four-cylinder engines include the 1.5-liter I4 LYX used in the 2018-2022 Chevy Equinox and GMC Terrain. The 1.2-liter I3 LIH is found in the 2020-2022 Buick Encore GX and Chevy Trailblazer. The 1.3-liter I3 L3T is in the 2020-2022 Buick Encore, Chevy Trailblazer, and the 1.4-liter LE2 9n comes in the 2016-2019 Chevy Cruze models.
In November, GM recommended a winter cover for the lower grille opening to lessen the occurrence of icing over. This was provided free of charge at any GM dealership under bulletin 21-NA-229. It was then recommended that the owner or a dealer tech remove it when the weather began warming up. These were first available in the 1920s in colder regions. To be honest, the suggestion of a winter cover seems like a very old solution in 2022.
A technical service bulletin over the issue was released in March 2020. It suggests if the problem continues, there is a “new design wide fin service part” to replace the Charge Air Cooler. So the icing over problems continues to plague these GM three- and four-cylinder turbocharged engines.
Owners are getting diagnostic trouble codes related to the intake of air. They include Engine Underboost, Engine Overboost, Intake Air Pressure Measurement System, Turbocharger Boost Sensor Performance, Engine Misfire detected, and Barometric Pressure Sensor Performance warnings. Most owners experience issues while the vehicle is first warming up. So it affects the first 15 minutes or so of driving in cold weather.
But there is a separate issue affecting 1.4-liter and 1.5-liter engines. The oil can become frozen, and water that circulates through the engine can be contaminated in the wastegate regulator solenoid valve. If this does occur, it might be able to be corrected with a cleaning, or replacement.
There is an ECM tune that can lessen the incidence of these issues occurring. It changes the rpm range when shifts occur. This lowers the frequency of overdrive engaging, so there are fewer overdrive shifts in cold weather.
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